1. Field of the Invention
The present invention relates to an apparatus for recording signals onto slant tracks of a recording medium with a rotary head, and more particularly to an apparatus having an erase head arranged for erasing recorded signals from narrow recording tracks.
2. Description of the Prior Art
Thanks to improvements in magnetic tapes and recording heads, a magnetic record/playback apparatus having a rotary head has been enhanced in its high density recording capability. For high density recording, various methods are proposed in which the width of each recording track is minimized and the number of tracks to be scanned by the rotary head during a given time is increased. It is usual to decrease the track width for increasing the recording density.
In erasing an editing track by an erase head, problems caused by mechanical error, track deviation, and tape traveling speed variation cause a part of a track adjacent to the editing track to be erased to reduce the track width and cause a part of the editing track to not be erased. Such a reduction in the track width or erasing failure appears more significant as the track becomes narrow. Accordingly, the signals retrieved from the beginning and concluding ends of an editing area of narrow tracks will be attenuated, thus producing a reduced quality image.
A method for minimizing a decline in the quality of a reproduced image of signals for data editing is disclosed in Japanese Laid-open Patent Publication 1-106382 (1989), in which data of each television frame as an editorial unit is recorded on a group of 15 consecutive tracks of a recording medium. In particular, one guarding track is interposed between two groups of tracks and each track is scanned for erasing by an erase head, which has an erasing width 2.5 times greater than the width of the track, so that any two adjacent erased regions are overlap each other by 1/2 track width. According to the method, the guarding track is scanned 3/4 by the erase head during erasing at the beginning and last portions of each editing area, thus leaving 1/4 track width as a margin of the guarding track width for the reduction of track width and erasing failure. However, the margin of the guarding track width should be optimumly 1/2 track width.